Interspinous internal fixation/distraction device

ABSTRACT

Disclosed are an apparatus for an interspinous fixation and/or distraction of vertebrae and a methodology for minimally invasive implantation of the apparatus in the spine of a patient. The apparatus corresponds to a pair of teardrop shaped lateral wing elements spaced apart by a central core element that may be selectively sized during the implantation process. The wings and central core are held together by a single threaded bolt and locking nut configuration resulting in a simple structure that may be easily implanted with minimal patient discomfort.

CROSS REFERENCE TO RELATED APPLICATIONS

This Patent Application is a continuation application claiming priorityto U.S. patent application Ser. No. 13/493,630, which is a continuationapplication claiming priority to U.S. patent application Ser. No.11/461,610, filed on Aug. 1, 2006, now issued as U.S. Pat. No.8,221,462, which claims priority to U.S. Provisional Application60/704,268, filed Aug. 1, 2005, the entire contents of which areincorporated by reference herein in their entireties.

FIELD OF THE INVENTION

The present technology relates to an interspinous fixation, and/ordistraction device designed for minimally invasive implantation in thespine. More particularly, the present technology relates to an apparatusthat may be implanted by herein disclosed methodologies in the lumbararea of the spine of a patient.

BACKGROUND OF THE INVENTION

The spinal column is a bio-mechanical structure principally composed ofvertebrae and intervertebral disks, along with ligaments, muscles,collectively whose primary functions may be regarded as includingsupport of the body as well as protection of the spinal cord andassociated nerve roots. The spinal column's body support functionalityinvolves distribution of weight from the various extremities and thetorso to the pelvis and legs. As individuals age, various adverse spinalcolumn conditions may develop that often result in back pain.Non-limiting examples of such conditions include spinal stenosis,thickening of spinal column constituent bones, facet antropathy, facetjoint arthritis, facet synovial cyst, annular tear, painful discdisruption, and segmental instability.

Currently, pain originating from such conditions (and others) may betreated with medications and/or surgically. However, it is often thecase that at present, in severe circumstances, such treatment requiresinvasive surgical correction. A principle goal for any such surgicalcorrection should be to minimize or eliminate the need for major surgeryin all patients and, most especially, for elderly patients.

Accordingly, to address such defective spinal column conditions andothers, there is need to develop devices and methodologies that areminimally invasive and that can be well tolerated by all patients,especially elderly patients.

Prior efforts to address such spinal column conditions have resulted inthe development of some forms of interspinous implants for implantationbetween adjacent spinous processes for the relief of pain associatedwith the spine. One such device is described in U.S. Pat. No. 6,695,842to Zucherman et al., entitled “Interspinous Process Distraction Systemand Method With Positionable Wing and Method” with an issue date of Feb.24, 2004. Such Zucherman et al. device includes a central spacer and apair of end wings in a complex configuration including a fastener with atapered head. The tapered head cooperates with a similarly taperedcavity portion of one of the wings to provide adjustment of the one wingrelative to the other wing.

A similar device is described in U.S. Patent Application PublicationU.S. 2004/0181282 A1 to Zucherman et al., entitled “Interspinous ProcessApparatus and Method With A Selectably Expandable Spacer” with apublication date of Sep. 16, 2004. The device disclosed in such '282publication is similar to that of the previously mentioned '842 patentbut provides a selectably expandable spacer that, by adjusting a screwmechanism, can be adjusted in place. The Zucherman et al. '282 publishedpatent application, like the '842 patent, suffers the same inherentcomplexity issues. In addition, from a surgery management perspective,the potential need to access such adjusting screw mechanism has thepotential for requiring additional invasive procedures on the patient.

While various implementations of implantable interspinous internalfixation/distraction devices have been developed, no design has emergedthat generally encompasses all of the desired characteristics ashereafter presented in accordance with the subject technology.

BRIEF SUMMARY OF THE INVENTION

In view of the recognized features encountered in the prior art andaddressed by the present subject matter, a present broad object is toprovide for improved interspinous fixation and/or distraction withminimally invasive implantation in the spine. In the same context, it isa present object to provide improved, minimally invasive interspinousimplants, developed so that they may be implanted through a relativelysmall incision (for example, such as 1-2″) in a manner such that thepresently disclosed implant remains safely outside the spinal canal. Insuch manner, a further present object is achieved for thereby desirablyavoiding any potential neurological injury or late epidural scarring.

Additionally, various of presently disclosed implants, when used inaccordance with the present methodology, may be implanted using local orIV conscious sedation, with the patient positioned in a standard proneposition, thereby allowing same day outpatient surgery and rapidambulation. Thus, another present object is to provide generally forimproved surgical-based treatments for certain defective spinalconditions of patients.

Per further present objects, exemplary implant devices in accordancewith the present technology function to stabilize the motion segment indistraction through the posterior elements. Such present methodology andapproach advantageously results in increased spinal canal area anddiameter, increased foraminal height and area, unloading of facet jointcontract forces, unloading of posterior annulus, and degreasedintra-discal pressure.

The potential positive clinical effects for some patients ofimplantation of the device in accordance with the present technology isdecreased radicular, leg pain by improved neural element compression inthe upright position and to decreased mechanical back pain by decreasedloading of facet joints and posterior annulus structures. In suchmanner, the present implant devices per present methodology,advantageously act as an internal splint or brace for spinal structures.

In an exemplary configuration, implants in accordance with the presenttechnology are provided with a pair of wings for lateral translationfixation, and provided with a central core element for longitudinalfixation and distraction. In accordance with aspects of some embodimentsof the present subject matter, the diameter of the central core elementmay be selected at the time of implant surgery from a number ofpre-constructed elements, based on spacing requirements determinedeither before or during the time of an actual surgical procedure.

In accordance with aspects of certain, additional embodiments of thepresent subject matter, methodologies and apparatus have been developedthat facilitate repeated assembly, disassembly, and reassembly of anexemplary present device during the implantation process so as tofacilitate fine-tuned sizing of the device even after initialimplantation. Such facility may be imparted in an exemplary form of thepresent subject matter through the provision of a single bolt andlocking nut design that secures in place all components of subjectexemplary implant and provides mechanical integrity to the finallyassembled device.

In accordance with certain aspects of other embodiments of the presentsubject matter, methodologies and apparatus have been developed tofacilitate implantation of the subject device in a pre-assembled formor, alternatively, in a modular fashion as necessary or as convenientduring implantation surgery.

Additional objects and advantages of the present subject matter are setforth in, or will be apparent to, those of ordinary skill in the artfrom the detailed description herein. Also, it should be furtherappreciated that modifications and variations to the specificallyillustrated, referred and discussed features, elements and/or stepshereof may be practiced in various embodiments and uses of the presentsubject matter without departing from the spirit and scope of thepresent subject matter. Variations may include, but are not limited to,substitution of equivalent means, features, or steps for thoseillustrated, referenced, or discussed, and the functional, operational,or positional reversal of various parts, features, steps, or the like.

Still further, it is to be understood that different embodiments, aswell as different presently preferred embodiments, of the presentsubject matter may include various combinations or configurations ofpresently disclosed features, steps, or elements, or their equivalents(including combinations of features, parts, or steps or configurationsthereof not expressly shown in the figures or stated in the detaileddescription of such figures). Additional embodiments of the presentsubject matter, not necessarily expressed in the summarized section, mayinclude and incorporate various combinations of aspects of features,components, or steps referenced in the summarized objects above, and/orother features, components, or steps as otherwise discussed in thisapplication. Those of ordinary skill in the art will better appreciatethe features and aspects of such embodiments, and others, upon review ofthe remainder of the specification.

BRIEF DESCRIPTION OF THE DRAWINGS

A full and enabling disclosure of the present subject matter, includingthe best mode thereof, directed to one of ordinary skill in the art, isset forth in the specification, which makes reference to the appendedfigures, in which:

FIG. 1 is an exploded view of an exemplary interspinous implant devicein accordance with the present technology, to show its exemplarycomponent parts;

FIG. 2 is a side elevation of a fully assembled exemplary presentimplant device;

FIG. 3 illustrates a portion of a lumbar section of a patient's spine,to illustrate exemplary conditions in which the present technology maybe applied; and

FIGS. 4, 5 and 6 respectively are schematic representations of anexemplary sequence of steps for implanting an exemplary present deviceaccording to the present methodology.

Repeat use of reference characters throughout the present specificationand appended drawings is intended to represent same or analogousfeatures, elements or steps of the present subject matter.

DETAILED DESCRIPTION OF THE INVENTION

As discussed in the Brief Summary of the Invention section, the presentsubject matter is particularly concerned with interspinous fixationand/or distraction devices designed for minimally invasive implantationin the spine, particularly, but not exclusively, in the lumbar area ofthe spine. It should be clearly understood that although the principleportion of the present disclosure is directed to apparatus andmethodologies for implantation of such apparatus in the lumbar area ofthe spine, such disclosure is not meant to be a limitation on thepresent subject matter as the apparatus and methodologies disclosedherein may also be associated with other areas of the spine.

Selected combinations of aspects of the disclosed technology correspondto a plurality of different embodiments of the present subject matter.It should be noted that each of the exemplary embodiments presented anddiscussed herein should not insinuate limitations of the present subjectmatter. Features or steps illustrated, described or suggested (eitherliterally or as discerned by one of ordinary skill in the art) as partof one embodiment may be used in combination with aspects of anotherembodiment or embodiments to yield yet further embodiments.Additionally, certain features may be interchanged with similar devicesor features not expressly mentioned or shown, which perform the same orsimilar function.

Reference will now be made in detail to the presently preferredembodiments of the subject interspinous implantable devices andcorresponding associated methodologies. Referring now to the drawings,FIG. 1 is an exploded view illustrating the component parts of anexemplary embodiment of a subject interspinous internalfixation/distraction device generally 100. As shown, devise 100 includesby way of example a pair of lateral wings 110 and 120. In this instance,such lateral wings may be preferably teardrop-shaped, and may be coupledtogether by way of an exemplary threaded bolt 130 and lock nut 140, 142configuration.

In the exemplary embodiment generally 100, a central core element(generally 150) is receivable over exemplary threaded bolt 130 by virtueof its illustrated central through bore 152. Threaded bolt 130 may bethreaded along a significant portion of one end thereof (see generallyexemplary region 132 shown in FIG. 1), to accommodate secure fixation ofvarious lengths and diameters of core element 150, as will be more fullydescribed herein.

The other end (generally 134) of threaded bolt 130 may be press fit orotherwise secured into a hole 112 in a relatively lower portion ofteardrop shaped wing 110. It should be appreciated that end 134 ofthreaded bolt 130 may be secured to wing 110 in any suitable manner.Non-limiting examples of other methods of securement, in addition to thepreviously mentioned press fitting, may include welding, gluing,threaded engagement, or providing a head on end 134 of threaded bolt130. It is also possible per the present subject matter to machine wing110 and threaded bolt 130 from a single piece of material.

Nuts 140, 142 may be threaded onto the threaded portion 132 of threadedbolt 130 after passing threaded bolt 132 through hole 122 formed in therelatively lower portion of teardrop shaped wing 120.

The foregoing arrangement collectively serves to secure the variouscomponents in assembled fashion, as illustrated in side view in FIG. 2.

The threaded end portion 132 of threaded bolt 130 may preferably containa small pilot hole 136, the function of which will be further explainedherein with respect to the device implantation process. A similar pilothole (not seen in the FIG. 1 view) may be provided in the opposite end134 of threaded bolt 132. Alternatively, such pilot hole 136 may extendthrough the entire length of the threaded bolt 132.

All of the various exemplary components corresponding in assembled formto device 100 as illustrated in representative FIGS. 1 and 2 mayadvantageously be constructed of biocompatible materials. Non-limitingexamples of such materials include stainless steel, titanium, highmolecular weight polyethylene (HMWPE), and polyetherether-Ketone (PEEK™,a high performance engineering thermoplastic resin manufactured byVictrex, plc.). Titanium may be advantageously employed to allow optimumpostoperative imaging while PEEK™ may be advantageous in selectedcircumstances as it mimics the modulus of elasticity of bone.

It is, of course, not necessary that all components of an exemplarypresent embodiment be made of the same materials. For example, wings110, 120, threaded bolt 130 and nuts 140, 142 may be made of titanium toobtain the benefit of improved postoperative imaging while central core150 may be made of PEEK™ for its bone mimicking modulus of elasticity.It should be clearly borne in mind that these specific examples arenon-limiting to the present technology as materials from which aparticular device of the present technology may be constructed may bechosen for a number of reasons and may depend, in part, on specificsituations unique to any one patient's particular requirements. In fact,the present technology may be practiced using not only the previouslymentioned materials but also with as yet undeveloped materials as theexact nature of the specific materials used is not critical to thepresent technology in its broadest forms.

With reference now to FIG. 3, there is illustrated a side elevationalview of a representative lumbar section 300 of an exemplary patient'sspine to which the present technology may be applied. Particular note istaken of the interspinous ligament 310, the supraspinous ligament 320,and the spinous process generally 330.

With reference now to FIGS. 4, 5 and 6, there is shown a sequence ofrespective illustrations demonstrating an exemplary methodology forimplanting an exemplary device 100 in accordance with the presenttechnology. Because of its modularity and unique design, exemplarydevice 100 can be implanted via a relatively small (for example, about1-2″) unilateral incision in the dorsolumbar fascia with the patientpositioned in the standard prone position. Current and previous deviceshave often required more extensive (and thus, more painful) bilateralfascia and muscle incisions. Such occurrences result disadvantageouslyin greater soft tissue disruption, increased pain, increased blood loss,and larger scars. Some of the current devices require surgery to beperformed with the patient in a decubitus (lateral) position. Suchposition often results in prolonged surgical time, and secondarily indifficulty with intraoperative x-ray imagining as well as decreasedsurgeon familiarity with the requisite surgical approach.

With further reference to FIGS. 4, 5 and 6, an exemplary surgicalprocedure with respect to implanting exemplary device 100 in accordancewith the present technology will be generally described.

FIG. 4 illustrates the pre-operative condition of the illustrated lumbarsection portion of the representative spine 300 to be addressed duringthe present surgical procedure. After surgically exposing the spinousprocesses 330, the interspinous ligament 310 and the supraspinousligament 320 (FIG. 3) are identified. A blunt probe may be used tocreate an entry portal through the interspinous ligament 310. Thesubstantially completely assembled device 100 may then be insertedthrough the interspinous ligament 310 to the opposite side.

The term substantially completely assembled is meant to convey theconcept that, during surgery, the central core element 150 may beswapped out with variously sized such elements to achieve optimal finetuning of the implant prior to final positioning of the lock nuts 140,142 into locking engagement. As is explicitly illustrated inrepresentative present FIG. 5, the exemplary device 100, due in part tothe low profile, teardrop configuration of wings 110, 120, may beinserted substantially fully assembled between the spinous processes330. The teardrop design conforms to lamina, broad surface area andprovides optimal medial lateral stabilization and fixation.

If positioning of the device 100 is now in the optimal transverse lie,then the small pilot hole 136 in the central shaft of threaded bolt 130,using, for example, a micro-lever device, can be used to tune the wings110, 120 (following the direction of arrow 510; see FIG. 5) into optimalposition, as illustrated in FIG. 6. Such rotation into optimal positioncan be accomplished with device 100 fully assembled or with wing andthreaded bolt separately assembled. With reference to FIG. 6, it will beobserved that upon rotation of wings 110, 120 into optimal position forlateral retention of assembled device 100, the posterior supraspinousligament 320 will be tightened and taut as a secondary aspect to thedistraction and stabilization of the spinous processes 330. Threadedopenings (see representative openings 340 in FIGS. 1, 5, and 6) providedin proximal and distal wing elements in accordance with the presentsubject matter allow for screw fixation (or equivalent) to the spinousprocess. Such feature maintains optimal position to maintain distractionand to avoid unintended displacement.

While the present subject matter has been described in detail withrespect to specific embodiments thereof, it will be appreciated thatthose skilled in the art, upon attaining an understanding of theforegoing, may readily produce alterations to, variations of, andequivalents to such embodiments. Accordingly, the scope of the presentdisclosure is by way of example rather than by way of limitation, andthe subject disclosure does not preclude inclusion of suchmodifications, variations and/or additions to the present subject matteras would be readily apparent to one of ordinary skill in the art.

What is claimed is:
 1. A surgical method comprising: exposing a pair of spinous processes having an interspinous space therebetween; inserting a device into the interspinous space, wherein the device comprises a proximal wing and a distal wing operably coupled by an elongated shaft; and rotating the device within the interspinous space such that the proximal wing is along one side of the pair of spinous processes and the distal wing is along the opposite side of the pair of spinous processes wherein the elongated shaft comprises a central core member extending between the proximal wing and the distal wing, the central core member comprising a bore for receiving a bolt therethrough; wherein the proximal wing is fixed to one end of the bolt; wherein the bolt is configured to extend through the bore of the central core member and through the distal wing; wherein a nut is positioned on the bolt after passing the bolt through the distal wing to secure the distal wing to the central core member; wherein the distal wing is rotatable with respect to the bolt; and wherein a pilot hole is configured in a central shaft of the bolt and wherein the pilot hole extends throughout the bolt and the nut for receiving a lever device for rotating the wings from a first position to a second position.
 2. The surgical method of claim 1, further comprising securing at least a portion of the device to at least one of the pair of spinous processes via a fastener.
 3. The surgical method of claim 1, wherein the bolt is threaded.
 4. The surgical method of claim 3, wherein the nut is threadable over the threaded bolt.
 5. The surgical method of claim 1, wherein at least a portion of the device is made of PEEK.
 6. The surgical method of claim 1, wherein the proximal wing and the distal wing are tear-shaped.
 7. A surgical method comprising: exposing a pair of spinous processes having an interspinous space therebetween; using a blunt probe to create an entry portal through an interspinous ligament into the interspinous space; inserting a device into the interspinous space, wherein the device comprises a proximal wing and a distal wing operably coupled by an elongated shaft; and rotating the device within the interspinous space such that the proximal wing is along one side of the pair of spinous processes and the distal wing is along the opposite side of the pair of spinous processes wherein the elongated shaft comprises a central core member extending between the proximal wing and the distal wing, the central core member comprising a bore for receiving a bolt therethrough; wherein the proximal wing is fixed to one end of the bolt; wherein the bolt is configured to extend through the bore of the central core member and through the distal wing; wherein a nut is positioned on the bolt after passing the bolt through the distal wing to secure the distal wing to the central core member; wherein the distal wing is rotatable with respect to the bolt; and wherein a pilot hole is configured in a central shaft of the bolt and wherein the pilot hole extends throughout the bolt and the nut for receiving a lever device for rotating the wings from a first position to a second position.
 8. The surgical method of claim 7, further comprising securing at least a portion of the device to at least one of the pair of spinous processes via a fastener.
 9. The surgical method of claim 7, wherein the bolt is threaded.
 10. The surgical method of claim 9, wherein the nut is threadable over the threaded bolt.
 11. The surgical method of claim 7, wherein at least a portion of the device is made of PEEK.
 12. The surgical method of claim 7, wherein the proximal wing and the distal wing are tear-shaped.
 13. A surgical method comprising: creating a unilateral incision; exposing a pair of spinous processes having an interspinous space therebetween; inserting a device into the interspinous space, wherein the device comprises a first wing and a second wing operably coupled by an elongated shaft; and rotating the device within the interspinous space such that the first wing is along one side of the pair of spinous processes and the second wing is along the opposite side of the pair of spinous processes wherein the elongated shaft comprises a central core member extending between the first wing and the second wing, the central core member comprising a bore for receiving a bolt therethrough; wherein the first wing is fixed to one end of the bolt; wherein the bolt is configured to extend through the bore of the central core member and through the second wing; wherein a nut is positioned on the bolt after passing the bolt through the second wing to secure the second wing to the central core member; wherein the second wing is rotatable with respect to the bolt; and wherein a pilot hole is configured in a central shaft of the bolt and wherein the pilot hole extends throughout the bolt and the nut for receiving a lever device for rotating the wings from a first position to a second position.
 14. The surgical method of claim 13, wherein the first wing and the second wing have a lower surface having a greater width than an upper surface.
 15. The surgical method of claim 13, wherein the incision is formed in a dorsolumbar fascia with a patient in a prone position.
 16. The surgical method of claim 13, wherein the bolt is threaded.
 17. The surgical method of claim 13, wherein, after rotation of the device within the interspinous space, the first wing and the second wing are secured to the pair of spinous processes via a fastener. 